Check for dead embedded iframes

My Wordpress site relies heavily on iframe content as I share music via the Soundcloud iframe widget on my site. I want to give the best service by only providing working Soundcloud widgets; is it possible to check your site to see if the iframes you have embedded in your posts are dead / no longer working?

Can anybody offer any advice?

For security reasons the page displaying the iframe has no access to what is inside the iframe if it comes from a different domain.

Does that mean it’s not possible then?

It is possible with modern browsers but only if the appropriate code is inserted on both sites to allow them to communicate. If you had that access to the sites where the iframe content is being loaded from then you wouldn’t need to perform the test.